1. Field of the Invention
The present invention relates to a method and an apparatus of effectively producing mask data files of partial areas for use in a charged particle beam exposure system or/and an inspection apparatus, based on a CAD data file of a semiconductor integrated circuit, and relates to a recording medium on which a program for executing this method is stored.
2. Description of the Related Art
FIG. 9 shows a schematic functional block diagram of a prior art apparatus for producing mask data files 12 of partial areas based on a CAD data file 11 by a computer 10, the file 12 being for use in a charged particle beam exposure system or/and an inspection apparatus.
In the CAD data file 11, design data covering al the area of a semiconductor chip are stored. With increase in degree of integration and multi-function of LSI, their circuits have been enlarging and data amount in the CAD data file 11 also have been increasing. A data amount further increases when the mask data file 12 is produced, which demands division of the mask data file 12 into a plurality of files if the increase in data amount exceeds an allowable amount on the exposure system side.
Therefore, an area on a chip is specified by an input apparatus 13, and data of the area is read out from the CAD data file 11 into the computer 10 to produce the mask data file 12, which processing is repeatedly performed. In the course of the repetition of processing by the computer 10, intermediate data files 141 and 142 are produced. The files 11, 12, 141 and 142 are stored on one or more hard disks.
In FIG. 9, a software configuration of the computer 10 is shown with functional blocks, which will be described below.
In a data expansion section 15, the CAD data of the area specified by the input apparatus 13 is read from the file 11, the data with a hierarchical structure is expanded and furthermore disassembled into basic figures decodable by an exposure system or/and an inspection apparatus to produce the intermediate data file 141. In a logic operation section 16, data in the file 141 is read, and logic operation for figures between layers, scaling, sizing and so on are performed and the results are stored into the intermediate data file 142. In a data format conversion section 17, data in the file 142 is read, and converted into a format readable by the exposure system or/and the inspection apparatus to store into the mask data file 12.
FIG. 10 shows a simplified mask pattern of the full area of a semiconductor chip. A hatched portion denotes a through hole pattern. An area specified by the input apparatus 13 is denoted by coordinates of a pair of diagonal points. For example, the full area is denoted as (X0, Y0)-(X2, Y1), wherein (X0, Y0), e.g. (0, 0), are an origin of a coordinate system for the full area 20.
In a case where the full area 20 is divided into two partial areas (X0, Y0)-(X1, Y1) and (X1, Y0)-(X2, Y1) to produce respective mask data files, the images of the mask data are partial areas 21 and 22 as shown in FIGS. 11(A) and 11(B). Origins of coordinate systems for the areas 21 and 22 are both (X0, Y0). Coordinates of the other diagonal point of the area 22 are (X2-X1, Y1).
In the prior art, the full area of a chip was divided into a plurality of partial areas, and each time when a partial area was specified by the input apparatus 13, processings in the data expansion section 15, the logic operation section 16 and the data format conversion section 17 were carried out to produce a mask data file 12, therefore processing of data of the full area cannot be collectively performed in each of the processing sections 15, 16 and 17, resulting in degrading processing efficiency and considerably lengthening the total time of producing the master data files 12 of the areas obtained by the division compared with a time for producing a mask data file with specifying the full area only once by the input apparatus 13.
Furthermore, the full area is firstly specified by the input apparatus 13 to produce the mask data file 12, and if a data amount thereof exceeds an allowable amount, the full area is necessary to be divided into a plurality of partial areas to repeat the above described processing, which makes the above problem remarkable.
Accordingly, it is an object of the present invention to provide a method and an apparatus of producing mask data files of partial areas with a shorter time in a case where the full area of a semiconductor integrated circuit is divided into a plurality of partial areas to produce the mask data files of the respective areas.
In one aspect of the present invention, there is provided a method of producing partial-area mask data files for use in a charged particle beam exposure system or an inspection apparatus based on a CAD data of a full area of a semiconductor integrated circuit, the partial-area mask data files being of respective partial areas obtained by dividing the full area, the method comprising the steps of: dividing the full area into a plurality of unit areas; producing a full-area mask data file based on the CAD data of the full area, and producing full-area header information having mask top data addresses of respective the unit areas and positional information on the unit areas; producing partial-area header information for each of the partial areas based on the full-area header information; and extracting mask data of each of the partial areas from the full-area mask data file based on the partial-area header information to produce the partial-area mask data file corresponding to the partial-area header information.
With this aspect of the present invention, since a full-area mask data file is produced from CAD data covering the full area of a semiconductor integrated circuit, processing therefore can be collectively carried out and thereby its processing efficiency is improved compared with a case where the full area is firstly divided into the partial areas, and further, the following processing becomes simple, resulting in that the sum of times for producing partial-area mask data files based on the CAD data can be shorter than that of the prior art.
Other aspects, objects, and the advantages of the present invention will become apparent from the following detailed description taken in connection with the accompanying drawings.